Expansion valve



July 1, 1930.

L. C. ROBERTS EXPANS ON VALVE 2 sheets sheet 1 Filed Jan. 19, 1927lNVENTOR L. C. FUEL-7W6 WITNESS July 1, 1930. L. c. ROBERTS 7 1,769,859

EXPANS ION VALVE Filed Jan. 19, 1927 2 Sheets-Sheet 2 2 6 O. I

Z6 y Y ZZ x wnwzss L.a/$JZ$$% Patented July l, 193% entree staresiseasse eATENr creme rnaoy'oun'ronnonners, or FARMINGTON, connncrrour,essrenoa 'ro THE Auro- MATIC REFRIGERATING conrranv, or rrnn rroan,oonnnorrccr, A CORPORATION OF NEW" JERSEY EXPANSION VALVE Applicationfiled January 19, 1927. Serial No. 162,077.

My invention relates more especially to expansion valves suitable forrefrigerating systems. 7

' There has been .some recent development in expansion valves to obtainone which would be less seriously afltectedby the high velocity of theliquid passing the expansion point than the valves ordinarily used. Thishas resulted in Combining two valves to divide the pressure dropexisting so that the velocity past the expansion points is divided intotwo stages, thev primary stage employing a pressure range of about 180lbs, from condenser pressure down to about 60 lbs. The secondary stageworks through a pressure range of about 60 lbs, to the pressure in theexpansion coils-usually about 15 to lbs. Such a combination, has valvesusing two diaphragms, each diaphragm regulating a valve which isactuated by the desired pressure for the two-stage expansion.

The object of the present invention is to provide means of improvedconstructionfor regulating the operation of expansion valves under thecontrol of thermostatic devices located in the refrigerated chamber, sothat when the room is cooled to a predetermined temperature, thethermostatic devices will 'relieve'the tension on the ex pansion valvein such a way as to permit it to close and act asa stop valve.

In its preferred embodiment, my invention contemplates a diaphragmexposed on one side to the pressure fluid on the low pressure side oftheexpansion valve which is permitted to close whenever there is asuificient rise of the pressure acting against the diaphragm. Actingagainst the other side of said diaphragm is a variable pressure mediumpreferably in the form of a spring,-the tension in said spring beingchangeable under the action of electromagnetically operated means underthe control of a thermostat in such a way that whenever the temperaturein the refrigerated chamber rises above apredeterminedmaximum, the loadon said diaphragm is increased sufficiently to open the expansion valveand whenever the temperature falls below a predetermined minimum, saidload is reduced sufficiently to permit said valve to close. g

Further details of the invention will appear in the description and byreference to the accompanying drawing in which:

Fig. l is a schematic view of a two chamber refrigerating plant showingthe manner of applying the invention. I f Fig. 2 is a sectional view ofthe combination valve.

Fig. 3 is a sectional view showing a n1odified form of valve.

Referring first to Figure 1-, a compressor 1 is shown driven by anelectric motor 2, current to which is "supplied from mains 3 andstarting switch 4:. At 5 is shown a switch which is operated by a backpressure device 6 that operates to start the motor when the backpressure from the refrigerating coils rises to a predetermined point.

At 7 and 8 are shown two refrigerating coils and adjacent to each coilis shown at 9 and 1O electric thermostats that operate to close thecircuit from supply conductors 3 to leads l1 and 12 that are'connectedto solenoid coils 13 and 14. The expansion valve shown at 15 in Fig. 1is illustrated in section 011 an enlarged scale in Fig. 2.

The valve body 15 is provided with an intermediate chamber 16 separatedfrom the high pressure pipe 17 by valve 18 and from the low pressurepipe 12 by valve 20. These valves are shown with springs 21 and 22 forpressing them to their seats. A diaphragm 23 bears against the lowpressure side of valve 18 and closes an opening to the atmosphere fromthe intermediate chamber 16. The pressure in chamber 16 therefore tendsto press the diaphragm away from th e valve and thereby allow the spring21 to seat the valve. The high pressure in pipe 17 also tends to closethe valve. Opposed tothese valveclosing tendencies is a spring 24 whichthrough a stem 25 maybe compressed by a lever 26 pivoted at one end I toa; fixed member 27, and at its free end to a connecting rod 28 on theend of which is a core 29 of the electric solenoid 13. At 30 shownavdiaphragm controllnig the secondary expansion valve 20. A spring31,;as

shown in Fig. 3 under adjustment of screw 32, may be used to apply apredetermined pressure that will allow the valve to open only when thelow ressure in the refrigerating coils falls below a predetermined InFig. 2 a construction is shownmhere tlw secondary valve 20 has theoutside surface of-its diaphragm placed under the influence of pressuresensitive to the temperature of the refrigerating room. ehaaiibenoverthe diaphragm '30 is connected by pipe 33 with a pipe 34 envelopingthe last pipe of the refri crating coils. The

'pe 3471s filled with a uid under pressure,

or example, an isolated volume of ammonia dawn from the high pressuresystem. when the li uid ammonia or other refriger- It reaches the lastpipe of the refrigerating coils, thetemperature of the fluid in theenveloping casing 34 will be lowered and will wntl'aet suflieiently torelieve the pressure on theupper. side of the dia hragm so that thevalve 20 can close an act as a stop veins, The vm nds y a e n e not bethermostatically controlled. It may be a expansion valve as shown inFigure 3, or in some cases a hand operated expansion zslve which simplyemploys a hand, adpzst- It, is to be observed that the valve are free ofstuffing oxes h hei a endant leakages n irieti n,

. Ln operation, when the rooms are cooled to a predeterminedtemperature, the ther- 9 andlO will shut off current from tho eolenoids13 and 14;, thus releasing the sparing tension above, the primary dia- 9ram. This release of pressure causes Cg: .sr'imary valve to close andinterrupts t ow of refrigerant. into the expansion This in turn producesa drop. in the pressure, which may be used to stop 3 operation of thecompressor by the usual back pressure control. When the room tem-. risesto the starting point of the i ostat, current is imposed upon the solenerd, which in turn produces a spring tension uponthe primary diaphragm,which opens the ,valve, admitting refrigerant and starts compressorthrough the rise in back ewe V r the mnnmg period of the comthe pressureunderneath the primary iaphragin is the intermediate pressure referredto. as being approximately 1km, this. pressure being maintainedconstautaccording to the tension on the diaphragm, as in the usualdiaphragm operatq ed valves. action of the solenoid is to bring anforce, that is responsive to the room 'mpprature, to make the primaryvalve an ion valve when the room temperature is'abowe the. predeterminedpoint and then the prorper temperature is reached to allow the valve toseat positively and act as a stop valve. When acting as an expansionvalve it divides with the secondary valve the work of reducing thepressure and thereby saves considerably the wear due to the rapid flowof fluid. When acting as a stop valve the wear is eliminated altogether.

I olaimz 1. In a fluid pressure expansion valve, the combination of avalve-body, a high-pres- A sure ipe, a low-pressure pipe, anintermediate 0 amber, an expansion valve interposed between saidhigh-pressure pipe and said intermediate chamber, a second expansionvalve interposed between said intermediate chamber and said low-pressurepipe, a movable diaphragm operating on each of said e pansi n a ves in airection tending t open said expansion valve, means for variably loadingthe diaphragm corresponding to the second-mentioned expansion valve inopposition to the pressure on the 10mmsure side thereof, andthermostatieallyeontrolled means for applying difierent con. stant presures f predetermin d magui tudes to the d aphragm corresponding to thefirst-mentio d expansion al e on the side Qpposite, to. that ex d to thepressure in said intermediate 0 amber.

2. In a fluid-pressure expansion valve, the combination of a valve bodyprovided with a high-pressu e inlet, a lo pressure outlet and anintermediate pressure chamber, an expansion valve interposed betweensaid high-pressure inlet and said intermediate pressure chamber, adiaphragm operating on said expansion valve, said diaphragm hei exposedon one side to the pressure in sai intermediate pressure chamber, acompres sion spring operative on the other side of said diaphragm inopposition to the. pressure in said intermediate pressure chamber, a secnd expansi n a e i rp sed tw en said intermediate pressure chamber andsaid low-preassure outlet, the last1mentioned ex pansion valve beingadapted in cooperation with the first-mentioned expansion valve tomaintain a substantially constant predetermined pressure in saidintermediate pressure chamber, and thermostaticall3l-0outrolled meansfor compressing and relaxin saidcompression spring for applying diferent fixed pressures in alternation to the first-mentioned expansionvalve whereby it is adapted to operate asv an expansion value when thetemperature is above a predetermmed point and to operate as a stop valvewhen e emp r re is elow said predetermined point,

3. In a fluid pressure valve, the combines tion of a valve body prov dedwith high pressure inlet and low-pressure outlet, and an intermediatepressure chamber, an ex,- panslon valve interposed between saidhighpressure inlet and said intermediate pressure chamber, a. secondexpansion valve posed between said intermediate pressure chamber andsaid low-pressure outlet, a diaphragm operative upon each of saidexpansion valves, each of said diaphragms being exposed on one side tothe pressure of the pressure fluid on the low-pressure side of theexpansion valve, variable pressure means operative upon the otherside ofthe diaphragm operating on the second-mentioned expansion valve, acompression spring operating on the other side of the diaphragmoperating on the first-mentioned expansion valve, andthermostatically-controlled means for imparting a predetermined amountof compression to said compression spring, the first-mentioned expansionvalve with its spring under compression and the secondmentionedexpansion valve under its variable loading, being adapted to maintain apredetermined substantially constant pressure in the intermediatepressure chamber, said first-mentioned expansion valve being adaptedwhen said compression spring is relaxed, to perform the functions of astop valve.

l. In a fluid pressure expansion valve, the combination of a valve-bodyprovided with a high-pressure valve-chamber, a diaphragm chamber havinga diaphragm forming a movable wall thereof, and a valve-port openingextending between said chambers, an expansion valve for said valve-portopening, said expansion valve being provided with a reduced stemextending through said valve-port opening and into engagement with saiddiaphragm, said valve body being provided with a second valve-chamber inopen communication with said diaphragm chamber, a second diaphragmchamber hav- 40 ing a diaphragm forming a movable wall thereof, and avalve-port opening between said second valve-chamber and said seconddiaphragm chamber, a second expansion valve for the last-mentionedport-opening, said second expansion valve having a reduced stem inengagement with the last mentioned diaphragm, thermostaticallycontrolled means for variably loading the lastmentioned diaphragm, andthermostaticallycontrolled means for applying dilierent predeterminedfixed loads to the first-mentioned diaphragm.

LEROY CLINTON ROBERTS.

